Let's talk about an issue I have with games.
Let's call it the knowledge issue.
The knowledge issue is the problem that you can't un-learn something intentionally. Story/puzzle games lose almost all value once you've played them, and a lot if someone spoils it for you
Horror games revolve around things happening suddenly and an atmosphere of apprehension. What's going to come for me? When will it show up? Am I safe? Do the rules change? What's behind this door?
Exploration games do, too. Once you've seen everything, you've explored it all. What more is there to do?
It's like reading a book. Why read it twice unless you've forgotten something?
A lot of games are easier if you know the exact mechanics, the limits where things start happening so you know exactly what you can and can't do.
Let's take Teleglitch. I just bought it. It's fun. I had no idea what to expect. The first time zombies burst out of a pipe I died simply because I didn't have time to process it. Now that I know that happens, I'm more careful. I know how many shots it takes on average to down the basic enemies. Two or three. I also know that I can craft the nailgun, how to find secrets, and other things I didn't.
There's a lot of fun in knowing you don't know things, and that there's more to learn.